What does oolemma mean?
The cell membrane of an oocyte
Noun. oolemma. The cell membrane of an oocyte.
Is vitelline membrane and oolemma same?
The oolemma is also called plasma membrane, plasmalemma or vitelline membrane.
What happens if polyspermy occurs?
In general, the entry of more than two spermatozoa into the egg cytoplasm, referred to as polyspermy, causes aberrant effects on meiosis completion or embryo development and hence embryonic death, due mainly to excess male centrosomes delivered into the egg.
Why is polyspermy avoided during fertilization?
Prevention of Polyspermy At fertilization, eggs are exposed to multiple sperm but entry of more than one sperm causes polyploidy, polyspermy, which results in abnormal embryo development. To ensure fusion of a single sperm, the egg becomes rapidly intolerant to additional sperm.
How does ovum prevent polyspermy?
An egg must be fertilized by a single sperm only. To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules.
What is vegetal pole of egg?
Medical Definition of vegetal pole : the point on the surface of an egg that is diametrically opposite to the animal pole and usually marks the center of the protoplasm containing more yolk, dividing more slowly and into larger blastomeres than that about the animal pole, and giving rise to the hypoblast of the embryo.
Who secretes Fertilizin?
The ovum
The ovum secretes a chemical named fertilizin (composed of glycoprotein = mono saccharides + amino acids). It mixes with the water to form egg water which attracts the sperms of its own species. The fertilizin of an egg interacts with the anti fertilizin of sperm of the same species.
What secretes zona pellucida?
The zona pellucida first appears in unilaminar primary oocytes. It is secreted by both the oocyte and the ovarian follicles. The zona pellucida is surrounded by the corona radiata. The corona is composed of cells that care for the egg when it is emitted from the ovary.
Which is the outermost layer of ovum?
So, the correct option is ‘ Zona pellucida’
What is meant by capacitation?
Definition of capacitation : the change undergone by sperm in the female reproductive tract that enables them to penetrate and fertilize an egg.
Which layer of ovum prevents polyspermy?
Zona pellucida layer of the ovum prevents polyspermy.